Effect of the Radon Background Fluctuation on the Low Activity Measurement of the ^214Pb, ^214Bi and ^226Ra

In this study, radon background fluctuation effect on the measurement of ^214pb, ^214bi and ^226ra low level activity concentrations were investigated in ventilated laboratory. for this purpose, detectors which had 150% and 20% efficiencies were used. in spite of the air ventilation, radon background fluctuation effect on the low level activity measurement was observed. 20% efficiency detector measured activity discrepancies were 5.7% for ^214pb, 8.7% for ^214bi and 5.8% for ^226ra. 150% efficiency detector measured activity discrepancies were 13.8% for ^214pb, 11.5% for ^214bi and 12.7% for ^226ra.